This study addresses the need for knowledge of prescribing trends in psychotropic treatments for the young. This topic has received little attention in either epidemiology or health services research. The lack of reliable information on usual prescribing practice patterns for children makes it difficult to know whether important changes are occurring over time. Yet, rates of drug prescription have increased dramatically in recent years according to regional studies and proprietary data; further, the possible failure of first-line treatments, e.g. methylphenidate for attention deficit hyperactivity disorder (ADHD), has led to recommendations for alternatives e.g., antidepressants. The extent of use of entirely new antidepressants, e.g. selective serotonin reuptake inhibitors (SSRIs), for this age group is largely unknown. Consequently, this study proposes to examine practice variations in psychotropic prescribing for those less than 20-years-old by assembling datasets for samples from Medicaid enrollee data from 4 states (Maryland, Ohio, Michigan and Nebraska) and from a staff model HMO (Kaiser Permanente Northwest region). In addition, survey data from several national sources, including physician-based office visits (NAMCS) and outpatient clinic- based visits (NHAMCS), will be examined. Major outcome measures reflect 3 specific aims. Aim 1: Psychotropic prevalence (total, drug class and specific agents) will be examined by practice setting (private practice, HMO, clinic, other), physician specialty [psychiatrists, neurologists, primary care (pediatricians and family practice] and payment source (commercial insurance, HMO, Medicaid); and stratified by age, gender, and geographic region. Aim 2: Trends in drug prevalence will be examined by observing yearly changes in treatments during the decade from 1987 through 1996. Aim 3: From the more detailed datasets (Maryland Medicaid and HMO) of continuously enrolled 5-14-year-olds, new versus continuing treatment prescriptions will be examined to determine if treatment duration is lengthening, and provide switching patterns, and dosage trends i.e., average daily dosage and combined (concomitant) psychotropic agents. Characteristics which differentiate psychiatrist from primary care visits will be another emphasis of the study. The study findings will provide reliable information on clinical patterns of usage--with implications for long-term effectiveness and satisfaction with treatment--as well as lay the methodologic groundwork for sampling plans and effect sizes to guide the development of future prospective (experimental) efficacy and (quasi- experimental) effectiveness studies. Psychopharmacology experts in government agencies (FDA and NIH), the pharmaceutical industry, child advocates and consumers each have drug information needs which the study proposes to fulfill.